US flagship offshore wind project Vineyard Wind 1, on schedule to begin delivering commercial power in 2023, is now expected to cost as much as $3.5bn – up some $500-$700m on earlier estimates, the CFO of the 800MW array’s developer, Álvaro Ortega Sebastián, has revealed.

That would represent a ballooning from the $2.8-$3bn regularly reported by the American and international media over the last several years. Approached by Recharge, Vineyard Wind declined to confirm forecast total capital costs for the project, and offered a “no comment” on the higher figure.